ACPI/IORT: Rename arm_smmu_v3_set_proximity() 'node' local variable

Commit 36a2ba07 ("ACPI/IORT: Reject platform device creation on NUMA
node mapping failure") introduced a local variable 'node' in
arm_smmu_v3_set_proximity() that shadows the struct acpi_iort_node
pointer function parameter.

Execution was unaffected but it is prone to errors and can lead
to subtle bugs.

Rename the local variable to prevent any issue.

Reviewed-by: Hanjun Guo <guohanjun@huawei.com>
Reported-by: Will Deacon <will@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Hanjun Guo <guohanjun@huawei.com>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Will Deacon <will@kernel.org>